spencer



April 30, 1929. J, A, SPEN ER 1,711,430

PILOT CUT-OFF FOR GAS BURNERS Filed Sept. 16, 1927 Patented Apr. 30,1929.

UNITED STATES PATENT OFFICE.

JOHN A. SPENCER, OF REVERE, MASSACHUSETTS, ASSIGNOR TO SPENCER THERMO-STAT COMPANY, OF CAMBRIDGE, MASSACHUSETTS,

CHUSETTS.

A CORPORATION OF MASSA- PILOT CUT-OFF FOR GAS BURNERS.

Application filed September 16, 1927. Serial 30.219338.

This invention relates to controlling means for gas consuming devicesand more particularly to an automatic safety cut on associated with themain burner or pilot, 1f one 18 used, for cutting off the supply of gasin the event that the main burner and pilot flame are both extinguished.

Heating by gas 18 now very common for water heaters, stoves, furnacesand certain types of automatic refrigerators and it is cus-- tomary tovary and in some cases cut oil the heat appliedby automatic or manuallycontrolled devices, the burners being often rela tively inaccessible.For the purpose of insuring the continuous automatic action of burnersof this character, it is customary to provide a pilot to relight themain burner when necessary, although the pilot need not be used if thecontrolling means is adapted merely to regulate the height of the flameof the main burner. It sometimes happens in th s latter case that theflame in the main burner is accidentally extinguished, or, in the casewhere a pilot is used and the mam burner is intentionally extinguished,the pilot also goes out; so that when the flow of gas to the mam burneris reestablished, it is not igmted, but escapes to the surrounding partsof the bullding in which the burner is located with the attendant risksto the occupants both from fire and asphyxiation.

Among the objects of the present invention, therefore, are to provide anautomatlc control or safety device responsive to the temperature of thepilot, if one is used, or to the temperature in the heated zone in whichthe gas is burned, which will function quickly and in a certain mannerto cut oil" the entire flow of gas both to the main gas burning devicesand to the pilot, if one is used, in the event that the flame isaccidentally extinguished; to provide for manually relighting the mainburner and pilot without the necessity of first warming the thermostat,and in this connection to provide a device in. which entirely automaticat the lowest temperature at which the thermostatic element chan s shapethus obviating the delay in relighting the burner due,to the hysteresisof the thermostatic element as well as the inertia of the moving parts;to provide in a device of this character an arrangement whereby the mainvalve may be located away from the high heat zone surrounding the burnerconsequently making it more durable and less likethe operation is againly to get out of order; to provide a sim le yet eificient apparatus formounting the t ermostatic element so as to protect it from extreme heatand yet permit it to be sensitively responsive to important changes oftemperature; to provide a means for introducin air to mix with the gasin the pilot if one 1s used; and geperally to improve devices of thischarac er.

Other objects and advantages of the invention will be apparent from thefollowing specification and appended claims when taken in connectionwith the accompanying drawings, in which:

Figs. 1 and 2 are central sections on the line 7 A-A in Fig. 3 showingthe valve opened and closed respectively;

Fig. 3 is a section on the line 33 in Fi 2;

Fig. 4 is a fragmentary section substantlally on the line 44 in Fig. 2';and

Fig. 5 is a fragmentary section on a large scale showing a detail ofconstruction.

The device comprises a valve casing I having .a gas inlet opening 2 andan outlet open-. mg 3, A valve seat 4 is provided between the soopenings 2 and 3, which cooperates with a valve generally indicated at5. This valve is mounted upon a shaft 6 extendin through the sides ofthe valve housing 1 am? provided at the outside with a suitable handle 7by 86 which the valve may be opened. A tension spring 8 is preferablyprovided between a point 9 on the valve and a suitable point within thevalve casing tending to close the valve. Any suitable valve constructionmay be used, but I have shown a sup orting member 10 having an aperture11 therein to receive a block 12, which is held in place by .a. screwbolt 13, the bolt 13also holding metal washers 14 and 15 havingtherebetween a resilient member 16 which may be of rubber, leather orother suitable material, the member 16 being adapted to engage the edgesof the valve seat 4 to out 01f the gas supply.

I provide a means for holding the valve in its open position comprisinga latch 17 pivoted to a rod 18 which is suitably mounted in the casing1, the latch havin a forwardly extending hook portion 19 adapted toengage over a shoulder 20 integral with the valve 5. The latch 17 isalso provided with an abutting portion 21 adapted to be engaged b aportion 22 integral with the valve 5 so 1; at when the valve is openedby rotating the handle 7, the latch will be rotated in a clockwise 1 0direction, as seen in Figs. 1 and 2 and the hook portion 19 engaged overthe shoulder 20 and hold the valve in its open position.

A tubular member 23 is slidably mounted in a cover 24'which is screwedto the casing 1 by two or more screws 25 and also in a plug 26 screwedinto the interior of the casing 1, this member being provided at itsinner end with a pin 27 which is adapted to bear against the latch 17 torotate it to release the valve 5 when the tubular member is moved to itsright-hand position, shown in Fig. 2. The outer end of the tubularmember is provided with a constricted passage 28 serving as a pilotflame opening. The tubularmember is made in two portions 29 and 30telescoping together and clamping between them a bimet'allicthermostatic disk 31, later to be described, these members beingfastened together in any suitable manner, as for example by a pm 31passing through the telescoping partsof both members. The member 30 isprovided with a diametrical elongated slot 32 into which protrudes theupper end of a gas nozzle member 33, which is suitably fixed to thevalve housing 1 and is provided with a bore 34 extending from its lowerend to a point adjacent to the top thereof, and a radial bore 35 openinginto the bore 34 and aligned with the bore 36 in the member 30. The bore34 is enlarged as by counterboring and internally threaded at its lowerend, as shown at 37, for the reception of needle valve 38. A duct 39extends through the lower wall of the valve housing 1 and the side wallof the nozzle member 33, and connects the outlet side of the valve withthe lower end of the bore 34. The plug 26 is threaded into the valvehousing 1, as shown at 40, and separates the gas chamber at theright-hand side of this plug, as seen in Figs. 1 and 2, from an airchamber 41, which communicates with the atmosphere in any suitablemanner, as for example by a port 42.

From the above description, the operation of the pilot will be obvious.The bore 39 communicates with the main gas supply at the outlet side ofthe valve and conducts the gas to the inside of the nozzle member 33where its flow is controlled by the needle valve 38, thence through thebores 34 and 35 to the bore 36 in the member 30, air entering at thispoint which comes in through the bore 42 and is drawn in and mixed withthe gas by aspirating, and the mixture then goes through an aperture inthe center of the thermostatic disk 31 and thence through the outletopening 28 of the pilot and serves there to lgnite the main burnerwhenever this action is necessary. v

I provide means for mounting the thermostatic disk to permit it to flexone way or another according to the temperature to which it issubjected. This means may comprise a pair of cupped members 43 and 44,the member 43 having two or more ears 45 adapted to be clamped betweenthe cover member 24 and the valve housing 1, and the member 44 havingbent over flanges or ears 46 clam ing it to the member 43. Between themem rs 43 and 44 I provide an annular spacing ring 47 whose internaldiameter is slightly greater than the diameter of the disk 31 and whosethickness is slightly (e. g. .005) greater than that of the disk wherebyfree motion of the disk is permitted. As. previously stated the disk isheld in position by bein clamped between members 29 and 30, a s oulderbeing formed upon member 29 cooperating with the end of member 30.

The disk 31 is preferably bimetallic, being formed of two componentdisks welded together, the materials such as iron and brass of therespective disks having different coeflicients of expansion. The disk 31is normally cupped (as by swaging) in such direction that the componentpart having the higher coefficient of expansion is on the concave side.Consequently upon raising the temperature of the disk the unequalexpansion of the materials forming the disk will cause a tendency toflatten the cupped surface until at a predetermined temperature a.

sudden curving in the opposite direction occurs, which reversal of shapewill be maintained until the temperature has been substantially lowered.Thereafter upon reaching a substantially lower temperature, the diskwill suddenly return to its initial shape. The materials and thicknessof the component parts and the degree of curvature are so chosen thatthe disk will snap in one direction when heated to the desiredtemperature (e. g. 120 F.) and will snap back at a lower temperature (e.g. 100 F.). Suitable materials are sheet brass and nickel steel having athickness of .005 and .005inches respectively and suitable cupping for adisk inches in diameter is .02 inches.

It will be understood however that the presentinvention is not limitedto any particular combination of materials having different thermalcoefiicients of expansion but is intended to embrace in its scope anycombination of materials having dissimilar thermal coeflicients ofexpansion sufiicient to cause the reversal of curvature. Furthermore,the two materials comprising the composite thermostatic disk may besecured together in any desired manner by riveting, soldering, brazing,or otherwise although it is preferred to unite the materials comprisingthe disk by welding or similar means to secure a substantiallyindivisible sheet.

The operation of the thermostatic portion of the device is as follows:when the pilot is lit at the end of member 29, heat is transmitted alongthis member to the disk, and in the event that the pilot is not used thetransmission of heat takes place through a solid member corresponding tomember 29 from the highly heated zone around the main burner to the diskas well as through the walls 7 to of the valve casing member 24 to theeriphery of the disk, in either case maintaining it in the positionshown in Fig. 1, that is convex to the left; and the latch 17 retains bthe valve 5 in its open position. However if the flame goes out and thediskcools to a predetermined temperature, it will abruptly reverse itsconcavity and snap to the position shown in Fi 2, thus pushing the rod27 to the right, lifting the latch 17, and permitting the valve tion ofaspring 8.

When it is desired to again open the valve, the handle 7 is turned whichopens the valve and in so doing brings the portion 22 thereof againstthe abutting member 21 of the latch, thus rotating the latch to lock thevalve in open position, as seen in Fig. 1, and simultaneously pushingthe rod 27 and the hollow member 23 to the left and flexing the diskback to its hot position, seen in Fig. 1. The burner may then be lit,but as in all thermostatic safety cut-offs, the handle to reset thevalve at its open position must be held until the thermostat has reachedits critical temperature. However, due to the fact that the linkconnectin and the valve operates in bot directions and resets thethermostat at its hot position the loss of time in holding thethermostat in position between its low critical temperature when itturns from hot to cold position, and

its high critical temperature, from cold to hot, is saved as well as theloss of time incident to heating the thermostat to a point where theforces therein are suflicient to overcome the inertia of the variousmoving parts of the device.

From the fore oing it will be obvious that one of the mem ers 43 and 44holding the thermostatic disk may be omitted leaving only a singlemember having an annular groove at its periphery in which the spacingring 47 and the disk 31 are received.

As many modifications may be made in this device without departin fromthe spirit of the invention, I do not WlSh to be limited except by thescope of the appended claims.

I claim:

1. In a gas burner controlling device, a valve ada ted to cut off theflow of gas to the burner, a latch engaging said valve normally to holdit in an open position, a bimetallic burner flame and to move said latchto permit the valve to close when the flame is extinguished and the diskcools to a predetermined temperature, and manually operable means foropening the valve and simultaneously forcing said thermostatic disk intoits hot position.

2. In a gas burner controlling device, a

saidvalve to closewhen the 5 to be closed by the acl the thermostat bvalve adapted to cut off the flow of gas to the burner a latch engagingsaid valve normally hold it in an open position, a gas pilot, abimetallic disk thermostat having its center fixed to the tube of saidgas pilot and adapted to receive heat therefrom and means engaged y saiddisk to trip said latch and permit pilot is extinguished and the diskcools to a predetermined temperature.

3. In a gas burner controlling device, a valve adapted .to cut ofl" theflow of gas to the burner, means tending to close said valve, a atchengaging said valve normally to hold it in an open position, a gaspilot, a thermostatic element which is perforated for the passage of gasto said pilot, means for conducting gas to said element and thence tosaid pilot, the pilot being bodil movable with said element, and meansinc uding a part of the gas conduit to said element for actuating saidlatch to release the valve when the pilot is extinguished and thethermostat cooled to a predetermined temperature the parts being soconstructed and arranged that opening the valve forces said element intoits hot position.

4. In a gas burner controlling device, a valve adapted to cut ofl theflow of gas to the urner, means tendingto close said valve, a latchengaging said valve normal] to hold it in an open position, a substantialy tubular member movably mounted in the valve casing having a pilot jetopening at its outer end, means fixed to the inner end of said tubularmember for actuating said latch, a thermostatic element having a portionrigid with said tubular member and adapted to move it longitudinally inresponse to changes in temperature thereof, a duct fixed with respect tosaid valve casing for conductin gas to said tubular member, the ductexten ing through an elongate "slot in said tubular member and having anaperture in line with the bore thereof, whereby the latch is released bythe action of the thermostatic element moving said tubular member andthus'permitting the valve to close when the pilot is extinguished 'andthe thermostat cools to a predetermined temperature, and manuallyoperable means for opening said valve, the parts bein so constructed andarranged that opening t e valve moves the latch the tubular member andthe thermostatic element to their hot position.

5. In a gas burner controlling device, a

valve adapted to cut oil the flow of gas to the r disk thermostatadapted to be heated by the b and to which it is fixed, a duct extendingfrom the outlet side of said valve and fixed with respect to said valvecasing for conducting gas to said tubular member, the-duct extendingthrough an elongate slot in said tubular member and having an aperturein line with the bore thereof, whereby the latch is released by theaction of the thermostatic disk moving said tubular member and thuspermitting the valve to close when the pilot is extinguished and thethermostat cools to a predetermined temperature, and manually operablemeans for opening said valve, the valve having an integral abutmentcooperable with a protruding portion of said latch so that when thevalve is opened the latch is rotated to engage it and also to move saidtubular member to flex said disk to its hot position.

'6. In a pilot cut-off mechanism for gas burners, a tube having a pilotjet at one end thereof, a pair of cupped members surrounding said tubeand in heat conducting relation therewith, one of said members having apcripheral flange adapted to overlap the periphery of the other memberto hold them together, a bimetallic disk thermostat, an annular spacingring separating the edges of said members, said ring having an internaldiameter slightly greater than the thermostatic disk and a thicknessslightly greater than said disk, the disk being mounted between saidmembers with its center free, a main gas supply valve, and meanscooperating with said disk for closing said valve if the thermostatcools below a predetermined temperature.

7. A mounting for a bimetallic disk thermostat comprising a pair of onped members fastened together at their peripheral edges, and an annularring separating said members near their peripheries, said ring having aninternal diameter slightl greater than the thermostatic disk and a tickness slightly greater than said disk, the disk being loosely mountedbetween said members.

8. A thermostat comprising a snap-acting element which moves abruptlyfrom one position to another when the temperature varies and a holderfor said element having opposing surfaces on opposite sides of theelement spacedapart a distance slightlygreater than thethickness of saidelement, thereby to permit the element freely to snap from one positionto another.

9. A thermostat comprising a snap-acting disk which moves abruptly fromone'posion opposite sides of the disk interengaging over the peripheryof the disk with an annular space thcrebetween to receive the peripheryof the disk and a ring surrounding the disk in said space, the thicknessof the rin being slightly greater than the thickness 0 the disk, wherebythe disk is free to snap from one position to another.

11.. A thermostat comprising a snap-acting I disk which movesabruptlyfrom one position to another when the temperature varies, asupport for the disk including members on opposite sides of the disk,one of the members being bent over the periphery of the disk and overthe other member with an annular space therebetween to receive theperiphery of the disk, and a ring surrounding the disk in said space,the thickness of the ring being slightly greater than the thickness ofthe disk, whereby the disk is free to snap from one position to another.

Signed by me at Cambridge, Mass, this 15th day of September, 1927.

i JOHN A. SPENCER.

